[racket-dev] Another JIT question

Did you try to pull out and simplify read-eval-print-loop until you can get
a stand-alone program that crashes? (The impl is in
racket/private/misc.rkt.)

Robby


On Sat, May 11, 2013 at 12:19 PM, Jon Zeppieri <zeppieri at gmail.com> wrote:

> I did:
>
> @@ -1555,9 +1570,9 @@ typedef void (*Scheme_Invoke_Proc)(Scheme_Env
> *env, intptr_t phase_shift,
>
>  /* Exploit the fact that these should never be dereferenced: */
>  #ifndef FIRST_TWO_BYTES_ARE_LEGAL_ADDRESSES
> -# define MZ_EVAL_WAITING_CONSTANT ((Scheme_Object *)0x2)
> -# define MZ_APPLY_WAITING_CONSTANT ((Scheme_Object *)0x4)
> -# define MZ_MULTIPLE_VALUES_CONSTANT ((Scheme_Object *)0x6)
> +# define MZ_EVAL_WAITING_CONSTANT ((Scheme_Object *)0x4)
> +# define MZ_APPLY_WAITING_CONSTANT ((Scheme_Object *)0x8)
> +# define MZ_MULTIPLE_VALUES_CONSTANT ((Scheme_Object *)0xc)
>  #endif
>
>
>
> On Sat, May 11, 2013 at 1:16 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> > Wild guess: Did you change the pseudo-values MZ_EVAL_WAITING_CONSTANT
> > and MZ_MULTIPLE_VALUES_CONSTANT to make sure they're not mistreated as
> > immediates --- or that a character is not mistreated as a pseduo-value?
> >
> > At Sat, 11 May 2013 13:12:54 -0400, Jon Zeppieri wrote:
> >> These all work:
> >>
> >> -> (write #\c)
> >> #\c
> >> -> (print #\c)
> >> #\c
> >> -> (display #\c)
> >> c
> >>
> >> It really seems to be the case that only functions that return
> >> characters have problems, and then, only those that return to the repo
> >> loop. For instance:
> >>
> >> -> (write (values #\c))
> >> #\c
> >> -> (values #\c)
> >> Segmentation fault: 11
> >>
> >>
> >> On Sat, May 11, 2013 at 11:29 AM, Matthew Flatt <mflatt at cs.utah.edu>
> wrote:
> >> > The last example seems to be the only one that uses `write', while the
> >> > others implicitly use `print'.
> >> >
> >> > Does
> >> >
> >> >  (write #\c)
> >> >
> >> > crash? How about
> >> >
> >> >  (print #\c)
> >> >
> >> > ?
> >> >
> >> > At Fri, 10 May 2013 21:19:25 -0400, Jon Zeppieri wrote:
> >> >> My experiment with immediately represented characters has gotten to a
> >> >> state where a non-JIT build passes all tests, but a JIT build fails
> >> >> (as in, segfaults) on the following program:
> >> >>
> >> >> #\c
> >> >>
> >> >> It also fails on:
> >> >>
> >> >> (integer->char 99)
> >> >>
> >> >> and:
> >> >>
> >> >> (define (foo x) (integer->char x))
> >> >> (foo 99)
> >> >>
> >> >> but not on:
> >> >>
> >> >> (define (foo x) (write (integer->char x)))
> >> >> (foo 99)
> >> >>
> >> >> So there seems to be a problem returning a character from a jitted
> >> >> function back to the repl. I haven't been able to figure out where
> >> >> this occurs, though. gdb's stack traces don't seem very useful for
> >> >> jitted code, and I can't use Sam's disassembler, because the process
> >> >> dies.
> >> >>
> >> >> Any idea where to look or what debugging tools might be useful?
> >> >>
> >> >> -Jon
> >> >> _________________________
> >> >>   Racket Developers list:
> >> >>   http://lists.racket-lang.org/dev
> _________________________
>   Racket Developers list:
>   http://lists.racket-lang.org/dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.racket-lang.org/dev/archive/attachments/20130511/fab7c353/attachment-0001.html>